Fuel-injection device for internal-combustion engines



Dec. 17, 1929.. H. R. RICARDO 1,740,316

FUEL INJECTION DEVICE FOR INTERNAL COMBUSTION ENGINES v Filed Feb. 3, 1.927

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FITIVG Patented Dec. 17, 1929 HARRY RALPH RICARDO, OF LONDON, ENGLAND FUEL-INJECTION DEVICE FOR INTERNAL-COMBUSTION ENGINES I Application filed February 3, 1927, Serial No. 165,701,

This inventionrelates to fuel injection devices for internal combustion engines and has for its object to provide a fuel injection device of the type employing a valve controlling 5 the delivery of fuel and disposed adjacent to the delivery orifice or orifices which will be reliable in operation, will not readily become choked and in which the formand direction of the fuel spray can be determined with a considerable degree of accuracy.

To this end according to the present invention there is combined with the valve. controlling the delivery of fuel a member disposed opposite and adjacent to a fixed seating, this member being carried by and moving with the fuel valve and arranged and operating so that as and when the valve is lifted off its seat to permit the fiow of fuel the member is moved towards or on to its seating with which it then cooperates to form one or more fuel injection passages or orifices.

The fuel valve may be either operated mechanically as by means'of a spring which is held inoperative except when the valve is to be lifted, or may be liftedautomatically by the pressure of fuel delivered behind it. In either case the valve is conveniently of the needle or mushroom type and may move, when lifting, either in the direction of fuel flow or in the opposite direction, while the membercarried by the valve and the seating with which this member cooperates are preferably both substantially conical.

The conical'or other member carried by the valve is preferably moved actually into contact with its seating or guide as and when the valve is lifted, while the fuel injection passages or orifices are constituted by one or more grooves or flats formed on or in the engaging surface of the conical member or of its seating or in both these surfaces. Alternatively, however, a stop may be provided to i prevent the conical or other member carried by the valve from moving into actual contact with its seating or guide as and when the valve is lifted.

As mentioned above the invention may be applied to fuel injection devices in which the valve is operated mechanically as by means of a spring which is held inoperative and in Great Britain February 25, 1926.

except when the valve is to be lifted, or may be lifted automatically by the pressure of fuel delivered behind it. The invention is particularly applicable, however, to fuel in jection devices of the kind employing automatically operated valves which move when lifting in the same direction as the flow of fuel. This type of fuel injection device possesses the important advantage that the valve stem does not have to pass through a pressure tight guide or stufiing box, as is the case with devices employing valves which when lifting move in the opposite direction to the fuel flow, and thus is less likely to become jammed and needs less accurate machining.

In known constructions of fuel injection devices employing valves which when lifting move in the direction of fuel flow, however, it is difficult to control the nature of the fuel spray since the spray from the valve seating is of a form which is not normally suitable for internal combustion engines and is moreover liable to serious variations caused by light lateral play of the valve. Further it is unsatisfactory to direct the fuel by passing it through a nozzle plate subsequently to its passage past the valve seat since the fuel is delivered from the larger diameter of the seat and a large volume of fuel would, therefore, be trapped on the combustion chamber side of the valve seat between the latter and the nozzle plate, which, for many reasons is undesirable.

With an arrangement according to the present invention, however, whether the .fuel injection device is of the type employing. a valve which when lifting moves in the direction of fuel flow or in the opposite direction, the nature and direction of the spray produced arecontrolled by the fuel injection orifice .or orifices formed between the member carried by the valve and the fixed seating or guide with which it cooperates and can thus be exactly determined. Thus, when the invention is applied to a fuel injection device employing a valve which lifts in the direction of fuel flow, the advantages of this type of valve may be obtained while the disadvantages previously associated with the employment of such valves are practically eliminated.

For example, when, as is preferred, the valve head carries a conical extension adapted to move towards a fixed conical seating so as to cooperate therewith to form one or more fuel injection passages when the valve is in its open position, these fuel injection passages may lead to a single central aperture through which a single cone or spray will thus be delivered in a manner previously associated only with fuel injection devices employing valves which lift in the opposite direction to the fuel flow. On the other hand, when the invention is applied to fuel injection devices employing valves of the type which lift in the opposite direction to the fuel flow, the tendency for the fuel injection orifice or orifices to become choked will be reduced owing to the motion towards and away from one another of the two members which cooperate to form these orifices, while the form and direction of the spray or sprays produced can be exactly determined.

The invention may be carried out in various'ways but four alternative constructions according to this invention are illustrated by way of example in the accompanying drawings, in which Figure 1 is a section through the longitudinal axis of one form of fuel injection device,

Figure 2 is a section on an enlarged scale on the line 22 of Figure 1,

Figure 3 is a section similar -to Figure 2 showing an alternative arrangement of structure providing injection passages.

In the construction illustrated in Figures 1 and 2 the device comprises a body portion Ahereinafter designated the sprayer body-to theinterior of which fuel is delivered through a passage B in a plug-like connecting member B. The other end of the sprayer body A is formed as a seating for a valve C of the mushroom type the stem C of which is mounted to slide in a guide bore A in the sprayer body A, this guide bore being provided with longitudinal grooves as shown at A through which fuel can flow. The upper end of the valve stem C carries a collar C the underside of which is acted upon by one end of a coil spring D the other end of which engages a suitable shoulder A in the interior of the sprayer body A so that the spring D tends to maintain the valve 0 normally in its closed position. Carried b the valve head C is a conical. extension which is adapted to be moved into contact with a similarly coned nozzle member F, mounted on the end of the sprayer body A, when the valve C is'moved into its open position by the pressure of fuel behind it. The conical valve head extension E has one or more, for example four, grooves E formed in its conical surface as shown in Figure 2,

this device.

valve according to this invention which opens these grooves serving with the interior of the nozzle member F to form fuel injection passages through which the fuel can pass from the valve C to a central fuel injection orifice F in the end of the nozzle member F. Instead of the grooves E as shown in Figure 2 flats E as-shown in Figure 3 may be provided on the conical surface of the member E to form the fuel injection passages as shown in Figure 3.

The nozzle member F may be adjustable so that the extent of movement permitted to the valve C before the conical extension E comes'into contact with the nozzle member can be varied. To this end the inner end of the nozzle member conveniently abuts against a shoulder A on the outside of the sprayer body and washers such as G of'difi'erent thicknesses may be interposed between the nozzle and this shoulder so as to vary the position of the nozzle member F relatively to the sprayer body.

lVith a fuel injection device constructed. according to this invention "it will be seen that by varying the shapeof the members oetween which the fuel injection passages are formed or by varying the number or dimensions of the grooves therein, the form of the spray may be varied to suit the particular re quirements of the engine with which the device is to' be used while, in constructions wherein the conical or other member carried by the valve actually engages with its seating, a proper centering of the member carried by the valve is ensured which thus tends to maintain the form and direction of the spray consistent and eliminates the necessity for an accurate and close fitting guide for the valve.

Further, in constructions such as that shown in Figures 1 and 2 wherein the fuel valve is opened directly by the pressure of fuel thereon, no piston is required as was previously necessary with valve controlled fuel injection devices producing a fuel spray of similar general form to that produced by Further when employing a in the direction of fuel flow, the valve when closing tends to draw back the fuel in the fuel injection orifices and thus to produce a quick cut offof the fuel spray without dribbling. The relative movement between the two members forming the fuel injection passages also assists in keeping these passage free from obstructions.w

lVhat I claim as my invention and desire to secure by Letters Patent is A fuel injection device for internal combustion engines comprising a body portion having a passage therethrough terminating in a valve seat, an orificed nozzle formed with an internal conical seat and having connection with said body portion adjacent the valve seat, a valve cooperating with said valve-seat to control the delivery of fuel through said passage and having a stem extending loosely through said passage, the parts being so constructed as to permit passage of fuel between the stem and the wall of said passage, a conical member carried by said valve in position to engage .said conical seat when said" valve is unseated, one of the conical enga 'ng surfaces being grooved to constitute a uel injection passage, a spring disposed within said passage and connected with said stem and normally retaining said valve on its seat, whereby pressure of fuel admitted to said body portion serves to open said valve and to seat said conical member to per-' mit passage of fuel through said grooves.

In testimony whereof I have signed my name to this specification.

HARRY RALPH RICARDO. 

